1. Field of the Invention
This invention relates to wheelchairs, particularly to power wheelchairs for use by handicapped and disabled persons.
2. Description of the Prior Art
Power wheelchairs are known and have been the subject of increasing development efforts to provide handicapped and disabled persons with independent mobility to assist them in leading more normal and active lives. Examples of power wheelchairs are found in U.S. Pat. Nos. D397,645; D404,693; 5,944,131; 6,129,165; 6,176,335; 6,186,252; and 6,199,647. While the power wheelchairs described in these patents have improved the state of the power wheelchair art over the prior motorized power wheelchairs, they all suffer from a common deficiency. They all include a resilient suspension, which is located forward of the front portion of the power wheelchair frame, for supporting the forward anti-tip idler wheels. This results in interference with the legs and feet of the handicapped person riding in the power wheelchair causing the legs and feet to be unnecessarily forwardly extended, and can result in injury to the handicapped person under certain conditions. Bumping of the users' feet due to the increased forward extension and pinching of their legs can occur because of the close proximity of their legs to the suspension assembly. Handicapped persons needing power wheelchairs have a variety of problems with their legs and feet, such as having little or no sensation in them Having the suspension assemblies, consisting of spring/strut combinations that are designed to compress and expand, in proximity to the user's legs could cause pinching of the clothing or skin of the user. In addition the anti-tip arm on the prior power wheelchairs forces the spring and strut upward and could cause injury to the user. The potential liability for such injuries can be substantial.
Even if the resilient suspension assemblies are covered by fenders having integral bumper members lying over and protecting them, the handicapped person's legs and feet must necessarily be extended forward and/or inward to accomodate the space taken up by the suspension assemblies. This causes the overall length of the power wheelchair occupant's footprint to increase, resulting in a greater turning radius and less maneuverability in tight areas and making the power wheelchair less practical. There are also limitations placed on the hardware available that can be used to support the person's legs and feet due to the suspension assemblies being positioned forward of the front portion of the power wheelchair frame. The width of the footrest that can be folded upward between the assemblies is decreased, and the flexibility in mounting individual leg rests with regard to the height and angle is also decreased.
Another deficiency of the prior power wheelchairs involves the aesthetics. Several components of the prior power wheelchairs such as the moving springs and spring struts must be covered by the body and fenders that extend beyond the front of the frame. These body/fender components are generally molded from plastic in an injection molding or vacuum forming process, and the required forward extending fenders must be stretched at the corners, thus presenting problems in the manufacturing process. A more aesthetically pleasing, as well as functional body would extend only as far as the front portion of the power wheelchair frame. Such a streamlined body would be easier to manufacture because of fewer curves and radiuses.